1. - walkthrough of classic hidden terminal problem in WiFi-
NS-3: an introduction
- walkthrough of classic hidden terminal problem in WiFi-
Anjan Rayamajhi

2. Todays topics Conceptual overview of NS3 Code Walkthrough:
Node, Application,Channel,Net Device, Helper functions
Code Walkthrough:
Hidden terminal problem
Discrete event simulation of Wifi
Example usage of Flow monitor, pcap tracing, NetAnim and PyViz

3. What is NS3
an open, extensible, core c++ discrete event network simulator
completely different than predecessor ns2 though porting ns2 modules written in c++ is possible
actively maintained at
highly modular with added features compared to ns2 such as Direct Code Execution

4. software organization of ns3

5. NS3 classes Nodes : computers, end systems, hosts
Application: user level softwars that make use of underlying networking. No concept of user level or system level applications.
Channel: models the link in terms of capacity, data rates etc. Eg. Wifichannel, CSMAchannel, PointToPointChannel
NetDevice: network interfaces that allow a node to communicate through a channel
Containers and Helper: Containers wrap Devices together into one object. Helpers provide easy objects to implement simulation and setup topology.

6. Code Walkthrough what is hidden terminal problem? Solution:
Use RTS - CTS to schedule transmission

7. Discrete Event simulation of wifi

8. walk through in code

9. Flow Monitor Hidden station experiment with RTS/CTS enabled:
Hidden station experiment with RTS/CTS disabled:
Flow 1 ( > )
Tx Packets: 2410
Tx Bytes:
TxOffered: Mbps
Rx Packets: 226
Rx Bytes:
Throughput: Mbps
Flow 2 ( > )
Tx Packets: 2411
Tx Bytes:
TxOffered: Mbps
Rx Packets: 243
Rx Bytes:
Throughput: Mbps
Hidden station experiment with RTS/CTS enabled:
Flow 1 ( > )
Tx Packets: 2410
Tx Bytes:
TxOffered: Mbps
Rx Packets: 415
Rx Bytes:
Throughput: Mbps
Flow 2 ( > )
Tx Packets: 2411
Tx Bytes:
TxOffered: Mbps
Rx Packets: 623
Rx Bytes:
Throughput: Mbps

10. pcap tracing
to be shown in the terminal

11. NSNAM offline code simulation visualization
reads simulation xml files and visualizes
comes with NS3 tar but needs to be installed using qmake

12. PyViz online code simulation visualizer installed alongwith ns3
make sure python-binding works
./waf --run <filename> --vis

13. References www.nsnam.org
Yet another Network simulator; M. Lacage, T. R. Henderson
FlowMonitor - a network monitoring framework for the NS3; G. Carneiro, P. Fortuna, M. Ricardo